Coseismic Slip Model of the 2021 Maduo Earthquake, China from Sentinel-1 InSAR Observation

Abstract

The 2021 Maduo earthquake occurred in the interior of the Bayan Har block of the Tibetan Plateau. We used space-born radar interferometry to study the coseismic deformation of this earthquake. Sentinel-1 InSAR observations along ascending and descending orbits provide the coseismic deformation. Pixel offset tracking method is used to complement InSAR observations near the rupture zone. The surface trace of the ruptured fault can be clearly mapped by InSAR observations. We constructed a three-dimensional coseismic slip model constrained by interferograms and pixel offset tracking in the form of a geodetic inverse problem. The coseismic slip model demonstrates that: (1) the Maduo earthquake was a left-lateral strike-slip event with moment magnitude of 7.4; (2) the peak slip is approximately 8 m and is located at a depth of 4 km; (3) a ‘shallow slip deficit’ of the Maduo earthquake is observed; (4) the ruptured faults are found to be dipping northward with a high dipping angle (80 degrees). This study has important implications on earthquake hazard evaluation of the Bayan Har block.

Impact of optical imagery and topography data resolution on the measurement of surface fault displacement using sub-pixel image correlation

“…Finally, high-frequency noise arises from random cross-correlation error, especially enhanced by image noise (Bornert et al, 2018(Bornert et al, , 2009Su and Zhang, 2016). The SAR results present a 100 m ground resolution and a cm-scale accuracy, which is consistent with the characteristics of typical multi-look SAR-derived products used to image earthquake ground displacements (e.g., Fielding et al, 2013;He et al, 2023;Jin and Fialko, 2021;Massonnet et al, 1993;Socquet et al, 2019;Tong et al, 2022;Zhao et al, 2021). Displacement amplitudes between the SAR and OIC measurements are consistent at the first order.…”

“…This earthquake generated a 160-km long surface rupture, which has been widely characterized using several geodetic (e.g., Fan et al, 2022;K. He et al, 2021;Jin and Fialko, 2021;Liu et al, 2021;Tong et al, 2022;Xiong et al, 2022;Yang et al, 2022;Zhao et al, 2021), field (Pan et al, 2022;Ren et al, 2022Ren et al, , 2021Xie et al, 2022;Yuan et al, 2022) and seismic data (e.g., Wei et al, 2022;Zhang et al, 2022). Field data report sparse surface ruptures with up to 2.6-2.9 m of horizontal displacement detected locally along primary fault strands (Pan et al, 2022;Ren et al, 2022Ren et al, , 2021Xie et al, 2022;Yuan et al, 2022).…”

Coseismic Deformation Obtained by Various Technical Methods and Its Constraint Ability to Slip Models of Maduo Earthquake

“…After the Maduo earthquake, many researchers studied the coseismic surface deformation characteristics through various methods such as field investigations, UAV photography, high-resolution optical images, InSAR, and GPS geodesy. They also studied the coseismic fault slip distribution of the Maduo earthquake and its stress impact on peripheral faults [3][4][5][6][7][8][9]. Based on the results of relocated aftershocks and field investigations, the earthquake was found to have occurred in the Jiangcuo fault zone, which is a branch fault located approximately 70 km south of the northern boundary fault of the eastern part of the Bayanhar block.…”

Three-dimensional coseismic displacements and slip distribution of the 2021 Mw 7.4 maduo earthquake: Synergy of SAR, InSAR and optical images

“…In the past year, there have been several geophysical studies (e.g. He et al, 2021;Zhao et al, 2021;Jin and Fialko, 2021;Chen et al, 2022;Tong et al, 2022) and geological studies (e.g., Ren et al, 2022;Yuan et al, 2022) to determine and investigate the characteristics of the seismogenic fault of the Mw7.4 Maduo earthquake. The geological studies were mostly focused on mapping fault geometry and coseismic surface ruptures.…”